The image projected by a projector may result in distortion due to off-axis projection and/or projection onto a non-flat or non-uniform projection surface. Typically, such projection distortion may be corrected by pre-compensating the video content prior to projecting the image, however this technique may not be ideal because it may cause a loss of potential brightness because the undistorted image created in this way is inscribed within the distorted field addressed by the scanner. In other words, by pre-compensating the video to reduce projection distortion, the duty cycle of the time the light is on versus the time the light is off is reduced, thereby lowering the brightness of the display. As a result, the user then either experiences a dimmer image, or the brightness of the image is required to be increased thereby wasting power.
Another common method for correcting projection distortion is to implement interpolation in the electronics of the projector to pre-distort the image or video content before it is projected, such that after projection the image will appear undistorted. In such an arrangement, the pre-distorted image has a resulting non-rectangular shape that is inscribed within the original area of the image source, assuming that the displayed image is intended to be rectangular. As result, some of the image source area is not fully utilized and the brightness will be non-uniform in the final projected image.
It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, if considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.